The present invention relates to electric motors, and more particularly to electric motors controllable to operate at a number of distinct output speeds.
Various electric motor controls have been used to control various electric motors to operate at multiple output speeds. Nevertheless, it would be desirable to have a new electric motor that is controllable by a less expensive controller to provide efficient operation at a number of distinct speeds.
Accordingly, the invention provides an electric motor that is controllable by an inexpensive controller to independently provide efficient operation at a number of distinct output speeds. The electric motor includes a single set of mechanical parts (e.g., housing, shaft, bearings, etc.) in combination with multiple sets of electromagnetic parts (e.g., first and second stators adapted to independently receive power from the controller and thereby produce first and second magnetic fields, respectively, and first and second rotating members connected to the shaft for rotation therewith and adapted to interact with the first and second magnetic fields), where the number of electromagnetic parts corresponds to the number of distinct output speeds of the electric motor. In some embodiments, each set of electromagnetic parts has a different configuration (e.g., a low speed set, a high speed set, etc.).
In one embodiment, the electric motor independently provides either a first or a second output speed. The motor includes two sets of electromagnetic parts (i.e., a first stator and a first rotating member, and a second stator and a second rotating member). The controller independently provides the electric motor either a first or a second power, where the first power corresponds to the first speed and the second power corresponds to the second speed. When the first power is provided, the first stator receives the first power and produces a first magnetic field. The first rotating member interacts with the first magnetic field and, as a result of the interaction, the rotor rotates at the first output speed. Similarly, when the second power is provided, the second stator receives the second power and produces a second magnetic field. The second rotating member interacts with the second magnetic field and, as a result of the interaction, the rotor rotates at the second output speed.
The electric motor of the invention can be used in many different environments requiring low numbers (e.g., 2, 3) of distinct output speeds. For example, the electric motor can be incorporated in a heating, ventilation, and air conditioning (HVAC) system to drive a blower assembly at either the first speed or the second speed. The first and second speeds provide a first or a second volume of air, respectively, to the environment the HVAC system is conditioning.
In other embodiment, the electric motor provides a different number of output speeds and/or is incorporated in other systems.